Project description: How do natural experiences shape the functional organisation of the developing brain? To address this question directly, we have been developing a novel robotic technology - the synthetic littermate (or \\\'surrogate\\\'). The current prototype consists of a biomimetic skin, which encloses camera, microphone, gyroscope, and accelerometer sensors. This allows us to collect naturalistic, multisensory experiences from within a litter of real developing rat pups. Rat pups spend the first two postnatal weeks in large huddles, wriggling closely in a synergy that aids thermoregulation: This primitive, natural \\\'huddling\\\' behaviour presents a rich and continuous source of sensory input to the developing pups, and so provides a unique opportunity to study self-organisation at the interface between natural and artificial systems. Driven by the rich multisensory experiences of a surrogate, self-organising models can be used to derive important predictions about the functional organisation in multisensory cortical areas, about which modern neuroscience knows relatively little. The approach could be used to predict, for example, the receptive field structure of multisensory neurons that represent combinations of somatosensory, visual, and proprioceptive spaces that interact to provide an agent with a sense of where it is in space (body schema).